Yellow supergiants with spectral types F-G show a complex
pattern of outer atmospheric structure with stellar wind and
activity indicators varying significantly for stars with
similar positions in the H-R diagram. The efficiency of the
processes driving their stellar winds and heating their
atmospheres is critically dependent on the evolutionary
position and surface gravity of each star. We present
high-resolution ultraviolet HST/STIS and HST/GHRS spectra
for a range of intermediate mass F and G supergiants,
including Alpha Car (F0 Ib), Beta Cam (G0 Ib), Beta Dra (G2
Ib), and Epsilon Gem (G8 Ib), and compare the atmospheric
properties of these stars with lower luminosity giants and
bright giants. We provide a systematic overview of the
supergiant atmospheric properties dealing particularly with
activity levels, the presence of hot ``transition region''
plasma, signatures of wind outflow, and the role of
overlying cool absorbing plasma that becomes increasingly
prominent for the cooler stars like Epsilon Gem.

This work is supported by HST grants for program GO-08280
and by NASA grant NAG5-3226.